Two hundred twenty-six consecutive surgical ptosis cases were carefully evaluated to establish the incidence of strabismus in ptosis. The overall incidence of strabismus in surgical ptosis patients was found to be 36%. Most remarkable were the findings in 113 congenital ptosis patients; 32% of these patients were found to have strabismus. Only 44% of these patients had entities previously described associating strabismus with ptosis. It is postulated that in four of the congenital ptosis patients (3.5%), strabismus developed as a result of their ptosis. In one of these patients, strabismus and amblyopia developed while the patient was being observed prior to ptosis surgery. This study demonstrates the need for careful ocular motility evaluation in all patients with ptosis. Ocular motility evaluation and follow-up is especially important in congenital ptosis, where the ptotic lid may, in fact, precipitate strabismus and amblyopia.